In the 3rd Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) forward link, multiple Dedicated Channels (DCHs) can be separately encoded and punctured, and then multiplexed for transmission over the same Dedicated Physical Channel (DPCH) (3GPP TS 25.212, “Technical Specification Group Radio Access Network; Multiplexing and Channel Coding (FDD)”, June 2005, Section 4). For each DCH transport channel, a variable number of information data blocks, may be encoded and simultaneously transmitted on the DPCH. The particular format of each transmission is normally signaled to a mobile terminal or User Equipment (UE) by a Transport Format Combination Indicator (TFCI), which specifies for each DCH transport channel the transport block size (i.e., number of bits contained in each transport block) and the number of transmitted transport blocks (plus additional parameters related to puncturing and channel encoding) (3GPP TS 25.302, “Technical Specification Group Radio Access Network; Services Provided by the Physical Layer”, September 2005).
However, the WCDMA standard requires that, under certain conditions, the UE be able to infer the transport format used for a transmission, without explicit signaling of the transport format combination indicator TFCI. In this case, the user equipment UE should rely on specific receiver signal processing functions for blind transport format detection. When, for each transport channel, the set of possible transport formats contains only one transport format with more than zero transport blocks, the user equipment should perform a specific processing function referred to as single transport format detection (3GPP TS 25.212, “Technical Specification Group Radio Access Network; Multiplexing and Channel Coding (FDD)”, June 2005, Section 4.3.1a), where the user equipment only needs to distinguish between the cases where the DCH transmission contains zero or one transport block (data rates equal to zero or full-rate).
In a WCDMA system, transmissions are made in Transmission Time Intervals (TTIs) of the duration of one or more 10 ms radio frames. Each 10 ms radio frame is further subdivided in 15 time slots, each containing 2560 chips. DCH data transmitted on a DPCH over one TTI can contain one transport block or multiple blocks.
A method for blind single transport format detection is suggested in 3GPP TS 25.212, “Technical Specification Group Radio Access Network; Multiplexing and Channel Coding (FDD)”, June 2005, Annex A (Informative): Blind Transport Format Detection, Section A.1.1. This method is based on an estimate of the power per bit of the dedicated physical data channel DPDCH, PDPDCH which is compared against an estimate of the power per bit of the dedicated physical control channel DPCCH, PDPCCH. Both power estimates are calculated per slot and averaged over one 10 ms frame. If the ratio PDPDCH/PDPCCH exceeds some threshold T, then it is declared that the full rate transport format has been detected, else it is declared that the zero rate transport format has been detected.
In the case where code blocks of different DCH transport channels are multiplexed and transmitted on the same DPCH channel, the above approach requires the identification of the DPCH slot data that correspond to the different transport channel.